EP3900115B1 - Electrical connection - Google Patents

Description

The invention relates to an electrical connection with a first electrically conductive component that has an opening, a bolt that has a head that extends along a first longitudinal axis and a threaded section, and an electrically conductive, plastically deformable (contact) ring a sleeve section having a through opening with a second longitudinal axis for receiving the bolt, and a bearing collar.

In order to establish an electrically conductive connection for power transmission between a plate-shaped component, for example a wall, and a connecting bolt for a grounding cable or the like, it is known to mechanically connect the bolt and the wall by means of an electrically conductive component in such a way that both are connected to the electrically conductive component are in contact. Such electrically conductive connections require a particularly good mechanical connection.

From the DE 10 2016 112 782 A1 and the DE 20 2018 101 358 U1 such an insert for connecting an electrical connection to a wall, for example a thin metal sheet, is known. In order to establish electrical conductivity between a cable and a metal sheet, a bolt (earthing bolt or grounding bolt) is attached to a metal sheet using a deformable sleeve. For this purpose, the connection must withstand tensile forces and torque, which can be generated by a nut, for example, when attaching a cable lug to the threaded bolt. During the installation of the threaded bolt in the sleeve, the sleeve is deformed in a defined manner. This causes the sleeve to expand radially outside of the metal sheet.

From the DE 10 2016 112 782 A1 it is known to provide the inner contour of the electrically conductive contact ring and the corresponding outer contour of the tie bolt with radii in such a way that a good surface pressure is achieved in the opening of the first component over a certain clamping area (grip) and especially for thin sheet metal. On the one hand, a good surface pressure is required for safe power transmission, on the other hand, it serves to absorb a torque that is introduced into the connection when installing a cable connection with a nut. The thinner the sheet metal into which the contact ring is mounted, the more difficult it is to absorb the mounting torque. the DE 20 2018 101 358 U1 therefore proposes not to design the opening and the outer contour of the sleeve section to be rotationally symmetrical.

In the case of these known solutions, it is felt that there is room for improvement in that the sheet metal contour can cut into the contact ring at high torques, and the contact surface can become too small, depending on the sheet metal thickness, in order to derive higher currents.

The object of the present invention is therefore to create an electrical connection of the type mentioned above which can support a high torque well and can transmit high currents.

This object is achieved with an electrical connection having the features of claim 1. In the case of an electrical connection according to the invention, the opening of the first component is provided with a passage for this purpose. A passage is understood here as a raised edge of the edge of the opening, which is designed in particular to be circumferential. The passage can be formed, for example, as a collar running around the opening, which is provided on the side of the first component facing away from the contact collar is and protrudes from the plane of the first component. According to the invention, a passage is thus introduced in the first component instead of a through hole that is easy to punch. In terms of stamping, this is just as easy to implement and offers the advantage of an enlarged contact surface for the contact ring. In this way, larger torques can also be supported.

Depending on the material used for the first component, the passage can be implemented as a small raised edge or with a significant height that is several times the material thickness of the first component. Thus, in the case of steel or aluminum sheets, the draft can have a height which is greater by a factor of 1.5 to 25, in particular by a factor of 2 to 10, than the thickness of the material of the first component.

According to a preferred embodiment of the invention, the passage is conical, in particular slightly, i.e. within the scope of a loose fit with an angle of, for example, about 1° to about 2°. Here, the inner diameter of the opening can taper towards the free edge of the passage. If the passage is slightly conical, the contact pressure can be additionally increased. This also serves to compensate for tolerances.

According to the invention, the bolt with a threaded section can be designed similar to a screw with a shank with an external thread and a head which is larger than this, the outer contour of which is adapted to the inner contour of the ring. During installation, an internally threaded tool such as a nut-like tool is used to pull the bolt into the ring and deform it. Alternatively, the stud may be hollow or blind-ended and internally threaded which cooperates with an externally threaded tool to pull the stud into and deform the ring. In this configuration of the bolt, it can be comparatively short (in the axial direction), possibly also shorter than the ring. With In other words, the bolt does not have to have a shank and can, for example, essentially consist of the head, the outer contour of which is adapted to the inner contour of the ring. When reference is made below to the (pull) bolt, both embodiments are meant, ie with an external thread or with an internal thread.

In order to create a connection for electrical contacts within the framework of lightweight construction and ever thinner components, which can absorb the greatest possible torque, according to one embodiment of the invention, the opening of the first component is not rotationally symmetrical and the sleeve section has at least partially a non-rotationally symmetrical outer contour. In other words, instead of supporting the torque only by friction, i.e. by purely rotationally symmetrical contours in which a tension bolt radially expands a contact ring, torque support via the outer contour of the ring is proposed for small sheet thicknesses. At the same time, this ensures sufficient contact pressure on the bore wall, which is advantageous for a tight connection and sufficient power transmission.

Here, the inner contour of the ring and the tension bolt can also be adapted to the outer contour of the ring in order to obtain a uniform wall thickness of the ring. Alternatively, the inner contour of the ring can still be designed to be rotationally symmetrical. There is either only a form fit between the ring and the wall or similar component, in which case the inner contour can remain rotationally symmetrical, or the shaped contour is provided on the inside and outside of the ring and thus possibly also on the outside of the head, which means that the circumference is at least approximately the same Wall thickness of the ring remains.

According to one embodiment, the sleeve section has a substantially cylindrical outer contour with at least one, in particular parallel to the Long axis aligned, flattening on. Alternatively, the sleeve section can have a polygonal outer contour at least in certain areas. The outer contour of the sleeve section is preferably adapted to the inner contour of the non-rotationally symmetrical opening in the wall in such a way that the sleeve section is guided in a rotationally fixed manner in the non-rotationally symmetrical opening in the wall.

The outer contour of the head can also be adapted to the inner contour of the sleeve section in such a way that the head is guided in the sleeve section in a rotationally fixed manner.

So that the ring can be supported on the plate-shaped first component when the bolt exerts a tensile force on the ring, the contact collar has a larger outside diameter than the rest of the ring. In this case, the contact collar can become deformed. This is particularly possible when the ring is made of a softer material than the bolt. A defined deformation of the ring or the contact collar is also favored if the contact collar is spaced radially from the sleeve section of the ring by a groove.

With regard to the inner contour of the ring and the outer contour of the head, the electrical connection according to the present invention is, for example, as shown in FIG DE 10 2016 112 782 A1 described trained. The head can have an outer contour which is produced at least in regions by rotating a first line curved with a first radius and spaced from the first longitudinal axis around the first longitudinal axis and is at least in regions larger than the inner contour of the through-opening of the sleeve section. Furthermore, the through-opening of the ring can have an inner contour which is formed at least in regions by rotation of a second line which is curved with a second radius and is spaced apart from the second longitudinal axis around the second longitudinal axis is created, the distance of the second curved line from the second longitudinal axis increasing from one end to the opposite end of the ring. In particular, the design of the inner contour of the ring and the outer contour of the head as a body of revolution, which are generated by curved lines, allows defined areas of the ring to be deformed by the head of the bolt in a targeted manner by widening.

It has proven to be particularly advantageous if the outer contour and the inner contour are matched to one another in such a way that the ring is radially expanded in an area located in the through-openings of the components to be connected when assembled and/or that the ring is in an assembled state located outside of the through-openings of the components area is radially expanded to form a bead or a projection. This achieves a particularly good mechanical connection between the ring and the components and between the bolt and the ring, which results in low electrical contact resistance. A defined local deformation of the ring by the head of the bolt also means that the forces required for this are comparatively low.

The design of the radii and the arrangement of the lines that form the outer contour of the head or the inner contour of the through-opening is preferably chosen so that the area of the head facing the shaft can be inserted with a loose fit in the area of the through-opening of the ring. which has the larger diameter. Also, the outside diameter of the shank of the bolt is preferably smaller than the smallest inside diameter of the through hole of the ring. Preferably, the first radius is different from the second radius. In particular, the first radius is smaller than the second radius. This causes the ring, and possibly also the bolt, to be plastically deformed when the head of the bolt is pressed into the through-opening of the ring. This will create a produces a particularly uniform deformation of the ring, which can bring the ring into contact with the inner walls of the through-opening of the wall in a defined manner.

The electrical connection also has a nut that can be screwed onto the bolt to pull it into the ring. In addition, such a nut can attach a connection terminal and/or a cable lug to the bolt.

In order to at least make it more difficult for the bolt to rotate relative to the ring, the outer contour of the head can be provided with a profiling in some areas as an alternative or in addition to the measures described above. Such a profiling can be, for example, knurling, which is provided in particular in a region of the head facing away from the shank. As an alternative or in addition to this, the profiling can also have longitudinal grooves and/or longitudinal ribs. Such a profiling can also be provided in the inner contour of the ring.

Further features, advantages and possible applications of the present invention also result from the following description of exemplary embodiments and with reference to the drawings.

Figur 1

in Schnittansicht einen bekannten elektrischen Anschluss,

Figur 2

in Schnittansicht ein plattenförmiges Bauteil eines erfindungsgemäßen elektrischen Anschlusses,

Figur 3

in teilweise geschnittene Seitenansicht den erfindungsgemäßen elektrischen Anschluss, und

Figur 4

in Schnittnsicht eine weitere Ausführungsform eines elektrischen Anschlusses.

They show schematically:

figure 1

a sectional view of a known electrical connection,

figure 2

a sectional view of a plate-shaped component of an electrical connection according to the invention,

figure 3

in a partially sectioned side view of the electrical connection according to the invention, and

figure 4

a further embodiment of an electrical connection in a sectional view.

the inside figure 1 The electrical connection shown has a bolt 1 and a (contact) ring 2, of which at least ring 2 is electrically conductive, with bolt 1 being inserted through ring 2. The bolt 1 extends along a first longitudinal axis I. The ring 2 extends along a second longitudinal axis. In figure 1 the two longitudinal axes coincide.

The bolt 1 has a head 3 and a shank 4 . The shank 4 is cylindrical in the embodiment shown and has an external thread 5, not shown in detail, onto which a nut, not shown, can be screwed. Alternatively, the shank 4 can be provided with an internal thread or a cross pin as a connecting means.

A first, for example plate-shaped, component is also designed to be electrically conductive and is part of the electrical connection. In figure 1 a thin first component 6a is indicated on the left-hand side, while a thicker first component 6b is indicated on the right-hand side of the figure. This serves to illustrate the differently sized clamping area (grip) in which the ring 2 can exert sufficient surface pressure on the first component, for example a wall. Deviating from the representation in figure 1 the first component typically has a constant wall thickness, at least in the area of the electrical connection.

The ring 2 consists of a softer, ie more easily plastically deformable, material than the bolt 1, for example aluminum. Ring 2 is through a sleeve portion 7 with a central opening and a radially projecting abutment collar 8 is formed. In the illustrated embodiment, the contact collar 8 is designed with a plastically deformable lip, with which the ring 2 can be supported on the first component (wall) extending transversely to the longitudinal axis. The plastically deformable lip of the contact collar 8 is spaced apart from the sleeve section 7 in the radial direction by a circumferential groove.

In the illustrated embodiment, the head 3 is designed as a body of revolution, the outer contour of which is produced by rotating a curved first line about the first longitudinal axis I. The line is, for example, a segment of a circle with a first radius R1. Deviating from this, the first line can also have areas with different radii of curvature and/or have an elliptical section. The first line can run at least approximately parallel to the first longitudinal axis I in the vicinity of the end facing away from the shaft 4 . The first line is arranged and designed relative to the first longitudinal axis I in such a way that the outer diameter of the head 3 increases starting from the end facing the shank 4 to the opposite end.

The through opening of the ring 2 can also be designed on the inside as a body of revolution, the contour of which is produced by rotating a curved second line about the second longitudinal axis. The second line is, for example, a segment of a circle with a second radius R2. The first radius R1 is preferably smaller than the second radius R2. The second line can also have areas with different radii of curvature and/or have an elliptical section. The second line can be near the in figure 1 lower end at least approximately parallel to the second longitudinal axis. The second line is arranged and designed relative to the second longitudinal axis in such a way that the inner diameter of the through-opening of the ring 2 starting from the in figure 1 increased upper end with the system collar 8 to the opposite end.

In principle, the head 3 and/or the ring 2 can essentially be as in one of the exemplary embodiments of FIG DE 10 2016 112 782 A1 be formed described, wherein on the ring 2 as in the DE 20 2018 101 358 U1 described non-rotationally symmetrical outer contour, for example a lateral flattening, can be provided.

the Figures 2 and 3 show details of an electrical connection according to the invention, with which a first component 6 embodied as a wall in the example shown is connected to a connection terminal 9 . For this purpose, for example, as in figure 1 shown insert, ie the bolt 1 and the ring 2, electrically conductively connected to the first component 6.

As in the Figures 2 and 3 is shown, the first component 6 has a through-opening 10 which is provided with a passage 11 . The ring 2 with the bolt 1 is inserted into the passage opening 10 , the contact collar 8 of the ring 2 resting on the first component 6 on the side facing away from the passage 11 .

In the example shown, the first component 6 has a wall thickness s that is significantly less than the height H of the passage 11 . The passage 11 thus forms a collar or sleeve-shaped section in the first component 6 for receiving the ring 2. Deviating from the example shown, the passage 11 can also be designed slightly conical, in particular such that the inner diameter of the passage 11 to its free edge (in the Figures 2 and 3 downwards) widens.

A mechanical connection is established between the bolt 1 and the first component 6 for the purpose of power transmission. In the assembly situation of figure 3 the bolt 1 has already been pulled into the ring 2 by means of a nut 12 so that the shank 4 has passed completely through the first component 6 and the head 3 of the bolt 1 is in the area of the through opening 10 of the first component 6 . The head 3 has penetrated so far into the passage opening of the ring 2 that the ring 2 is plastically deformed by means of the head 3 . Here, the head 3 has widened the ring 2 in such a way that its outer surface is pressed radially with the through-opening 10 and the passage 11 . In this way, electrical contact with a low transition resistance is achieved between the bolt 1 via the ring 2 with the inside of the passage opening 10 and the passage 11 . In addition, the head 3 has radially widened the section of the ring 2 protruding through the through-opening 10, ie the section facing away from the shoulder 8, forming a bead-like overhang. As a result, the ring 2 is also pressed with the first component 6 in the axial direction, ie between the contact collar 8 and the bead-like overhang. The connection terminal 9 is to be clamped between the nut 12 and the ring 2 on the bolt 1 . As a result, the connection terminal is electrically connected to the first component 6, for example a wall, by means of the insert.

In the figures 1 and 3 is the bolt 1 with similar to a screw with the shank 4 with an external thread 5 and compared to this enlarged head 3 is formed, the outer contour of which is adapted to the inner contour of the ring 2 . In figure 4 an alternative embodiment is shown, in which the bolt 1 is sleeve-shaped, ie hollow, with a through-opening 13 and has an internal thread 14 . This can interact with an externally threaded tool to pull the bolt 1 into the ring 2 and deform it. In figure 4 the passage 11 is not shown, but as in the Figures 2 and 3 be trained.

Reference List

1

bolt

2

ring

3

head

4

shaft

5

external thread

6

first component (wall)

6a

first component

6b

first component

7

sleeve section

8th

attachment collar

9

terminal block

10

passage opening

11

Draft

12

mother

13

opening

14

inner thread

I

first longitudinal axis

R1

first radius

R2

second radius

s

Thickness of the first component 6

H

Height of draft 11

Claims (15)

1. Electrical connection comprising an, in particular platelike, first electrically conductive component (6) which has an opening (10), a bolt (1) comprising a head (3) which extends along a first longitudinal axis (I) and a thread section (5, 14), and an electrically conductive plastically deformable ring (2) having a sleeve section (7) comprising a through-opening with a second longitudinal axis for receiving the bolt (1), and a bearing collar (8), characterized in that the opening (10) in the first component (6) is provided with a passage (11).
2. Electrical connection according to Claim 1, characterized in that the passage (11) is configured as a collar which extends around the opening (10) and is provided on the side of the first component (6) which faces away from the bearing collar (8).
3. Electrical connection according to Claim 1 or 2, characterized in that the passage (11) has a height (H) which is greater than the thickness (s) of the material of the first component (6) by a factor of 1.5 to 25, in particular by a factor of 2 to 10.
4. Electrical connection according to any one of the preceding claims, characterized in that the passage (11) is conical, wherein the inner diameter of the opening (10) tapers toward the free edge of the passage (11).
5. Electrical connection according to any one of the preceding claims, characterized in that the opening (10) of the first component (6) is not rotationally symmetrical and that the sleeve section (7) has a non-rotationally symmetrical outer contour.
6. Electrical connection according to Claim 5, characterized in that the sleeve section (7) comprises a substantially cylindrical outer contour having at least one flattened portion which is in particular aligned parallel to the longitudinal axis (I).
7. Electrical connection according to any one of the preceding claims, characterized in that the outer contour of the head (3) is adapted to the inner contour of the sleeve section (7) such that the head (3) is held in the sleeve section (7) in a rotationally fixed manner.
8. Electrical connection according to any one of the preceding claims, characterized in that the bearing collar (8) has an outer diameter which is relatively larger than the rest of the ring (2).
9. Electrical connection according to any one of the preceding claims, characterized in that the ring (2) is made of a softer material than the bolt (1).
10. Electrical connection according to any one of the preceding claims, characterized in that the bearing collar (8) is radially spaced apart from the sleeve section (7) of the ring (2) by a groove.
11. Electrical connection according to any one of the preceding claims, characterized in that the head (3) has an outer contour which is produced, at least in regions, by rotating a first line which is curved with a first radius (R1) and spaced apart from the first longitudinal axis (I) about the first longitudinal axis (I) and, at least in regions, is larger than the inner contour of the through-opening of the sleeve section (7), and that the through-opening of the ring (2) has an inner contour which is produced, at least in regions, by rotating a second line which is curved with a second radius (R2) and spaced apart from the second longitudinal axis about the second longitudinal axis, wherein the distance of the second curved line from the second longitudinal axis increases from one end to the opposite end of the ring (2).
12. Electrical connection according to any one of the preceding claims which additionally comprises a nut (12) and a connecting terminal (9) and/or a cable lug.
13. Electrical connection according to any one of the preceding claims, characterized in that the bolt (1) is configured with a shaft (4) comprising an external thread (5) and a head (3) which is enlarged relative thereto.
14. Electrical connection according to any one of Claims 1 to 12, characterized in that the bolt (1) comprises an internal thread (14) .
15. Electrical connection according to Claim 14, characterized in that the bolt (1) is sleeve-shaped with a through-opening (13) in which the internal thread (14) is provided.

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